Passive systems that utilize a natural power such as a pond, plant, or microorganisms, is expected to be a cost-effective method for acid mine drainage (AMD) treatment. The Ningyo-toge mine, a non-operational uranium mine located in Okayama Prefecture, Japan, generates AMD containing arsenic and iron. To quantitatively study arsenic and iron ion removal in an artificial wetland and pond, chemical reactions were modeled and incorporated into the GETFLOWS (general-purpose terrestrial fluid-flow simulator) software. The chemical reaction models consisted of arsenite and ferrous oxidation equations and arsenic adsorption on ferrihydrite. The X-ray diffraction analysis of sediment samples showed ferrihydrite patterns. These results were consistent with the model for arsenite/ferrous oxidation and arsenic adsorption on ferrihydrite. Geofluid simulation was conducted to simulate mass transfer with the utilized topographic model, inlet flow rate, precipitation, and evaporation. The measured arsenic and iron ions concentrations in solution samples from the wetland and pond, fitted well with the model. This indicated that the main removal mechanism was the oxidation of arsenite/ferrous ions and that arsenic was removed by adsorption rather than dilution.

中文翻译：

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GETFLOWS结合化学反应在日本封闭矿山人工湿地中通过水铁矿共沉淀去除砷的应用

利用自然动力（例如池塘，植物或微生物）的无源系统有望成为酸性矿山排水（AMD）处理的一种经济高效的方法。Ningyo-toge矿是位于日本冈山县的一家非运营性铀矿，其产生的AMD中含有砷和铁。为了定量研究人工湿地和池塘中砷和铁离子的去除，对化学反应进行了建模，并将其合并到GETFLOWS（通用陆地流体流动模拟器）软件中。化学反应模型包括亚砷酸盐和亚铁的氧化方程以及砷在三水铁矿上的吸附。沉积物样品的X射线衍射分析显示出水铁矿模式。这些结果与亚砷酸盐/亚铁氧化和亚铁在亚铁酸盐上的吸附模型是一致的。进行了土流模拟，以利用所利用的地形模型，入口流速，降水和蒸发来模拟传质。湿地和池塘溶液样品中测得的砷和铁离子浓度与模型非常吻合。这表明主要的去除机理是砷/亚铁离子的氧化，并且砷是通过吸附而不是稀释来去除的。